Feed flexibility at lube refineries is managed to minimize risk of producing lube base stock outside of fit for purpose product quality standards. Crude approval procedures have long been established based on predictions of the ability of a crude to meet oxidative stability and fit for purpose standards.
Assessment of toxicological hazards is based on processing experience and measurement of a MI of processed base oils. However, obtaining the MI measurement takes a few weeks and it cannot be measured on all plant batches although good practice dictates that it should be checked during routine quality monitoring or as part of significant feed or process changes.
A compositional model based on multi-ring aromatics in base oils can be used for estimation of toxicological hazards. Also, conservative ultraviolet absorption spectra of aromatic hydrocarbons (UV aromatics) and viscosity index (VI) thresholds are set for the purpose of monitoring potential toxicological hazards of base oils. Other techniques, such as High Detail Hydrocarbon Analysis (HDHA) can also be suitable.
The development of a screening method is needed that can estimate toxicological potential of hydrocarbons. Also, the development of a screening method is needed that will reduce the barriers to entry of demonstrations (e.g., cost, time, human resources, tied-up tankage, etc.), reduce the number of demonstrations needed, allow for more effective capture of feed flexibility credits, and reduce product giveaway during Group I/II/III/III+ base stock production at refineries.